Interplay mechanisms between progesterone and endocannabinoid receptors in regulating bull sperm capacitation and acrosome reaction.

After ejaculation, sperm show a limited capacity for transcription and translation. In the oviduct, most of the signalling in sperm is nongenomic and is mediated through membrane receptors. Studies have shown that the cation channel of sperm (CatSper), cAMP, cGMP, protein kinases, and tyrosine phosphorylation are involved in the nongenomic signalling of progesterone (P4) in sperm. However, it is not known whether there is an interplay between P4 and cannabinoid receptors 1 and 2 (CB1 and CB2), transient receptor potential vanilloid 1 (TRPV1), CatSper channels, cAMP, inositol trisphosphate receptor (IP3R), and mitogen-activated protein kinase (MAPK); these potential regulators are involved in the regulation of capacitation and the acrosome reaction. In the present study, selective blockers of CB1, CB2, TRPV1, CatSper channels, cAMP, protein kinase A (PKA), IP3R, and MAPK were used to identify their involvement in P4-mediated bull sperm capacitation and the acrosome reaction. Selective blocking of any one of the molecules caused a significant reduction in P4 signalling (p < 0.05). Interestingly, blocking these molecules in combination followed by treatment with P4 resulted in the complete absence of capacitation and the acrosome reaction. Blocking a single receptor was not able to eliminate the P4-induced capacitation and the acrosome reaction. In addition to the CB1 and CB2 receptors, there may be other signalling pathways that mediate P4 signalling. In conclusion, P4 signalling exhibited interplay with the cannabinoid receptors. The regulation of sperm capacitation and the acrosome reaction also involved cAMP, PKA, l-type and T-type calcium channels, TRPV1, inositol trisphosphate, and MAPK.

Electroencephalographic attributes of goats under conscious state.

Electroencephalographic studies were undertaken in goats to correlate with normal behavioral states and physiological conditions. Duplicate EEG records from 4 adult female goats (8-12 months, 10 +/- 2 kg body wt), using bipolar scalp electrodes placed in occipital region, were obtained to evaluate electrical responses of brain during different postures and states of alertness. EEG recordings were obtained under comfortable conditions and after adequate training of animals. EEG frequency (Hz) during lying down posture was significantly (P<0.05) lower compared to standing posture (32.63 +/- 1.34 Vs 38.63 +/- 1.03), the individual values ranging between 29 to 42 Hz. EEG amplitudes however varied non significantly between two states with respective values of 5.75 +/- 0.25 and 6.11 +/- 0.26 microV. During light and deep drowsiness, the frequencies recorded were 21.63 +/- 0.94 and 13.00 +/- 0.68 Hz, whereas amplitudes were 12.45 +/- 0.55 and 19.96 +/- 0.68 microV, respectively and the differences being statistically significant (P<0.05). Mean EEG frequencies of the order of 7.13 +/- 1.14 and 3.25 +/- 0.49 Hz and amplitudes of 16.59 +/- 2.55 and 19.86 +/- 3.19 microV were recorded during light and deep sleep, respectively. General trend indicated that frequency decreased and amplitudes increased with onset of drowsiness and these changes were proportional to the state of consciousness.